Flexor Digitorum Superficialis Wrist Tendon

tendines musculi flexoris digitorum superficialis ad carpum

The four FDS tendons converge at the wrist to enter the carpal tunnel in a double layer — the middle (ring) finger tendons superficial and the index (little) finger tendons deep. At wrist level the FDS tendons are enclosed in the common flexor tendon sheath with the FDP tendons, and the relationship between the layers determines tendon repair technique after carpal tunnel-level injuries.

Region: Forearm

Clinical Relevance

Clinical Notes

FDS tendon injuries at the wrist require precise identification of the four individual tendons and their relationship to FDP before repair. Carpal tunnel synovitis most commonly involves the FDS tendon sheaths, producing the hypertrophic tenosynovitis visible on wrist ultrasound. The distinctive 'Bunnel' position of the FDS tendons at the wrist (middle and ring on top, index and little below) must be respected during tendon transfer harvest to avoid disrupting uninjured tendons.

Pathology

Common Injuries & Conditions

FDS Tenosynovitis at Wrist

Synovial proliferation around the FDS tendons at the wrist in inflammatory arthropathy, producing wrist swelling and finger flexion stiffness, visible as enlarged tendon sheaths on ultrasound or MRI.